Beet-slicing machine



y 25, 1954 J. R. URSCHEL El AL BEET-SLICING MACHINE 4 Sheejbs-Sheet 1 Filed Jan. 2, 1955 z WW 0% May 25, 1954 J. R. URSCHEL ET AL BEET-SLICING MACHINE 4 Sheets-Sheet 2 Filed Jan. 2, 1955 y 25, 1954 J. R. URSCHEL ET AL BEET-SLICING MACHINE 4 Sheets-Sheet 5 Filed Jan. 2, 1953 f IIENTOR Z '7. W Qhjfl f e Qhsciie y 25, 1954 J. R. URSCHEL El AL BEETSLIC NG MACHINE Patented May 25, 1954 UNITED STATES ATENT OFFICE BEET-SLICIN G MACHINE Joe R. Urschel and Gerald W. Urschel, Valparaiso, Ind.

13 Claims. 1

This invention has to do with machines for slicing rollable sliceable articles such as beets from which the foliage and root extensions have been removed, and primarily concerns such a machine which comprises a chute or guide trough along which the beets are successively propelled by an impeller to attain a speed at which the momentum of the beets is sufficient to carry them through a bank of slicing knives for performing the slicing operation.

Because of the slippery surface of beets which have been topped, derooted and blanched, they are diflicult to handle and to hold by mechanical means while a slicing operation is being performed thereon. This character of blanched beets in the process of being sliced by commercial canners has been particularly vexatious because accurately formed slices are highly desirable as well as having the slices extend as nearly perpendicularly to the major axis of the beet as possible. Holding the rather fragile blanched and slippery beet properly orientated with respect to slicing knives has been dimcult and heretofore incapable of being performed with satisfactory speed. The principal object of this invention is to overcome these difficulties by the provision of a machine and method of beet-slicing by means of which the slicing operation involves rolling the beet along a trough or guide surface which serves to utilize gyroscopic action of the beet for maintaining its principal axis transversely to the direction of movement as it rolls along the guide surface, whereby the beet can be projected by its own inertia and gyroscopic action with sufficient force into a bank of knives while properly oriented with respect thereto that the beet will be sliced at desired parallel planes therein as the beet carries into and through the knife bank.

A mere specific object is the provision of a beet slicing machine wherein there is a beetguiding trough extending spirally within a plane, the trough having an inner terminus adjacent an extending perpendicularly to such plane and having a discharge terminus disposed radially more distantly from such axis and there being an impeller rotatable about the axis and adapted to sweep along the trough for propelling and accelerating a beet while moving it along the trough from the inner terminus toward the cuter terminus from which the beet is dischargeable by virtue of its momentum, together with a bank of slicing knives adapted to cut the catapulted beet into slices while accommodating the passage of the slices between the knives.

A further object is the provision in a beet-sliding machine of the above character of a decelerator for the beet slices in the form of a tortuous chute into which the slices enter as they emerge at high speed from the discharge side of the knife bank.

Another object is the provision of a beet-slicing machine wherein a beet impeller rotating at constant speed about an axis adjacent the inner terminus of a spiral beet-guiding trough is adapted to engage a beet which is substantially at rest at such terminus by a section of the paddle adjacent the axis that is moving at relatively slow curvilinear speed to avoid crushing or bruising the beet and to accelerate the beet as it is moved by the impeller along the trough by engaging such beet with impeller portions progressively more distant from said axis and moving at correspondingly greater curvilinear speed whereby the beet attains a substantial speed as it approaches the discharge terminus of the spiral trough.

Still another object is the provision of a slicing knife unit having a novel knife anchorage and tensioning means for holding the knives in echelon formation.

The above and other desirable objects inherent in and encompassed by the invention are elucidated in the ensuing specification, the appended claims and the annexed drawings, wherem:

Fig. l is a perspective view of a beet-slicing machine constructed according to the principles of this invention.

Fig. 2 is a side elevational view of the machine shown in Fig. 1.

Fig. 3 is an enlarged perspective view of a knife frame and a plurality of beet-slicing knives secured therein, said knives constituting a knife bank employed in said machine for slicing beets successively propelled against and through such knife bank.

Fig. 4 is an enlarged fragmentary view partlyin section, showing part of the machine frame, said knife bank, a casing containing a spiral beet-guiding trough for directing beets into the knife bank, and an impeller for propelling the beets along the trough.

Fig. 5 is a fragmentary sectional view taken on the line 5-5 transversely of the beet-guiding trough to illustrate the same in transverse section.

Fig. 6 is an enlarged transverse section taken in a vertical plane substantially coincident with the impeller rotational axis and in the direction indicated by the arrows associated with the dotdash line 6-6 in Fig. 4.

Fig. 7 is a fragmentary sectional view taken on the line 7-1 of Fig. 4.

particularly to Figs. 1 and 2 thereof, the machine can be seen assembled within and upon aframe.

10 having a substantially square skeleto'n' top H supported at its corners by four upright legs i2, I3, l4 and I5. Any desired number of brace members It, H, I8 and i9 may. be provided for the legs. A beet-receiving hopper'2l'is mounted A side wall opening (not upon the frame top i I. shown) is adapted to feedbeets successively from the hopper through a chute 22 onto an inner terminus 23 f a beet-guiding trough 2 formed Within sidewalls 25- and 26 of a circular casing 21. In Fig. 4 the principal portion of side wall 25 has been broken away to expose the inner side ofthe side wall 26 and the spiraltrough complement 28 thereof cooperating with a similarly formed complement 2-9 in the wall 25 for forming the spiral trough 24; see Fig. 6. Trough 23 is coincident with the plane indicated by the dot-dash line indicated by the reference characters P-P in Fig. and extends spirally fronithe inner terminus-23;,Fig. 4, teen outer terminus 3 I-. This inner guide trough terminus 23 is adjacent to an axis a-a, shown at a point in Fig. 4, about which-a beet impeller is rotatable and the beet discharge terminus 3! is disposed more distant radially from such axis. In Fig. 6 the axis ar'a can be seento constitute the principal axis of a drive shaft 33 for the impeller 32.

Refe'rringnow to'Fig. 6, the circular casing side wall 26=canbe seen to have an axial collar-like extension 34 whereon there is an annular flange- 35 secured rigidly to a radial flange 38 upon a tubular shaft housing 3? by means of a circle of cap screws 38-of which one is shown. The shaft housing 31 has'a horizontal mounting flange 39;.

Figs. 4 and 6, formed. integrallywith its lower side secured by bolts 4| to a bracket 42 mounted upon the frame top H by a weldedconnection shown at 42 in Fig. 6.

The impeller driving shaft 33 isrotatively supported upon a ball bearing unit 43 and a needle bearing unit 44 carried within the tubular. housing 31. The inner endof the shaft 33 embodies a circular flange 45' constituting a hub for a shank portion 46' of the impeller 32. A pair of cap screws 41 secure the impeller hub 43 to a portion of the flange 45'that is disposed diametrically opposite from a section of such flange to which a semi-circular counterweight 48 is securedby cap screws 49. is for counteracting the centrifugal force developed by the impeller 32 and imposed radially upon the drive shaft 33 during rotation of this shaft and of said propeller.

A- notch 51 of curved contour is formed in the impeller hub 43 to faciliate entry of beets into i the casing 21 from the bottom portion of the chute 22. A beet registering with and coming into contact with the curved periphery of the notch 5i will be part way into the casing 21 and thus be capable of entering all of the way into such casing. for resting. upon the lower parts of the circular trough complements 28 and 29 before the impeller completes its next revolution whereby the beet thus entering the casing.2l' will This counterweight 48 be squarely engaged by the impeller shank l6 attendant to being propelled thereby about the axis a a during the succeeding revolution.

Circular end wall 25 of the casing 21 is attached to and mounted upon the circular side wall 26 in spaced relation with respect thereto by'means of=a=plurality of: spacer sleeves 52 and bolts 53 respectively extending through said sleeves and through registering holes 54 and 55 irrthe walls 25 and 26. Threaded end portions 51 and 58 of these bolts 53 have nuts 59 turned thereunto' for drawing the circular walls 25 and 26-firmly against the ends of the sleeves.

Power for driving the impeller shaft 33 is derived from an electric motor M, Fig. 2, which by means of a pulley-6| upon the armature shaft 62 thereof drives a belt 63 trained over such pulley and also trained over a pulley 3 mounted upon andconstrained for rotation with the shaft 33.

The spiral shoulders or complements 23 and 29 of the beet-guiding trough 24 extend spirally from the troughinner terminus 23 about the axis a,a while gradually increasing in radial spacing from such axis within the plane extending perpendicularly to the'axis a-aand coinciding with the linen-10 in Fig. 6. From a position slightly above the plane indicated by the line 5-5 in Fig. 4, a trough 65 is formed by a pair of shoulders or trough complements 63 and Bi constituting downwardly extending extensions respectively from the radially inner terminals of the trough complements 28=and 23. Thus in Fig. 5 it canbe seen that the troughs 24 and 35 are in opposed relation to form a beet-guiding passage 68. This passage 68 extends downwardly coextensively with the previously described discharge terminus 3| of the trough 24. The lower part of the'trough 24 as viewed in Fig. 4 is formed by shoulders39 on respective trough extension members 10; see Fig. 'I. These shoulders 39 are continuations respectively of the shoulders 28 and 29v ofthe casing walls26 and 25. Each of the cast metal extension members 13 comprises a flange 'H' at itsupper end and secured by cap screws 72 to-flanges 'l'1 at the upper edges of notches M formed in the casing side walls 25 and 26; Lower edge parts lfi of the cast extension members '10 are held in spaced relation by spacer bolts 1'5 having reduced-diameter threaded end portions 15 projecting throughholes-l5 inthe lower edge parts 75 and having nuts- 15 turned thereonto. Upper vertical sides E3 of members 'lmprojecting upwardly from the shoulders 63, fit into the notches '12. Thus the trough extensions 10' and particularly the converging shoulders 89 thereof complement the opposed shoulders 66 and 31; Figs. 5 and 'I, of the trough 65 in forming the lower part of the beet.- guiding passage 68'.

A cast bracket 18 comprises a generally rec.- tangular central'portion 9. with downwardly extending flanges 81 at opposite edges of said central portion. The lower edges of the flanges 8! are welded or otherwise secured to cross members id and w respectively of the machine frame it); see'Figs. 1 and l. Rectangular central portion Til'of the cast-bracket i8 is arranged perpendicularly to the beet-guiding passage 68 and contains a rectangular opening 82 which registers with the passage 68; A beet-slicing knife supporting frame 83 is mounted upon the bracket i3 by means-of acap screw 84 0f which the shank projects into a notchi in an ear 8B. projecting fromthe lower. edge. of an end plate. 81' and a;

wing-headed screw 84 of which the threaded shank extends through a hole 84* in the bracket portion 19 into threaded relation with a threaded hole 86 in an ear 86 projecting from the lower portion of an end plate 88. Frame end plates 87 and 88 which are rectangular are urged apart by four similarly constructed thrust rods 89, 90, 9| and 92 for placing the bank of beet-slicing knives 91 having opposite ends secured to the plates 87 and 88 under tension. Details of the thrust rod i and its association with the frame end plates 81 and 88 are illustrated in Fig. 8. The end of this rod 9| adjacent the end plate 87 contains a threaded cross 90 and is drawn tightly against the inner face of the plate 8'! by a cap screw 9d. The opposite end of the thrust rod 91 contains an unthreaded recess 9E3 wherein there is an anti-friction compression ball 90" pressed against by the inner end of the threaded shank 90 of a cap screw 94* turned into a threaded hole 94 in the end plate 88. When the cap screw 94* is rotated in the direction for advancing inwardly through the end plate 88, such end plate 88 will in fact be caused to separate from the plate 87 while the inner end of. the threaded shank 98 bears against the anti-friction ball 90 thereby exerting tension in the knives 91 and placing a thrust in the rod 9I. Each of the rods 89, 90, 9! and 92 has a cap screw 94 associated with its end adjacent the plate 81 and a cap screw 94* associated with its end adjacent the plate 88 as illustrated in Fig. 8.

Each of the frame end plates 81 and 88 has a knife holding bracket 95 secured to its inner face. Each bracket 05, Figs. 3 and 4, is assembled from a pair of flat bar-like bracket components 535 and 95 shown in detail in Figs. 9, 10, 11 and i2. Bracket component 95 has a bottom edge and a vertical inner edge 95 opposite an outer edge notched to form a series of shoulders 95 and riser faces $5? A series of bolt-receiving holes IZI are driiled horizontally into the component 55 through the vertical edge 95 to extend respectively through the riser faces 95 excepting that two of such holes communicate through the uppermost riser face which has twice the height of the riser faces therebelow. The lower of the two holes i2i emerging through the uppermost riser face 85 is counter-bored at I22 at the end adjacent the vertical edge 95 to receive half of the large diameter mid-section I23 of a double ended bolt :24. Those holes I2I below that receiving the bolt :2 are similarly counter-bored at I25 to receive the heads of bolts I25, and these counter-bores I25 being progressively deeper from uppermost to lowermost so the bolts I26 of equal shank length can project through and beyond their associated riser faces 95 A bolt I2! is insorted in the uppermost hole IZI. Bracket component 95 has a lower edge 85" and an inner vertical edge 95. The outer edge of bracket component 95 also has a series of shoulders 95 and riser faces 95 and this bracket component is also provided with horizontal bores I2I countersunk at i22 and I25 to receive bolt enlargement I23 and the heads of respective bolts I26 as explained with respect to bracket component 95*.

After all of the bolts I24 and I26 are in place as illustrated in Figs. 9 and the bracket components 95 and 95 are assembled with their vertical edges together as illustrated in Fig. 12. Such assembly is maintained by bolts I28 extending through horizontal holes I29 in these bracket components. Each of thebrackets 95 thus assembled with the various knife-attachilarly placed, said knives are mounted upon the shanks of these bolts as illustrated in Figs. 3, 4 and 12. Nuts I 32 are turned onto th ends of the bolts I24, I26 and I21 for holding the knives in place, the center knife being uppermost, the.

two knives immediately adjacent the center knife being paired with one another and at an equal lower elevation from the center knife, the next pair of knives being at the same elevation next lower from the first pair, etc., in echelon formation as is visible in Fig. 3, and the cutting edges IIlI of these knives extending lengthwise thereof and disposed upwardly as illustrated in Fig. 4. Thereupon the cap screws 94, Fig. 8, are rotated to separate the plate 88 from the plate 8'! and place the knives under sufficient tension to make them incapable of transverse deflection despite their thinness and their short dimension between their cutting edges IOI and their back or opposite edges I 0|. The knife bank unit is now ready for mountin upon th bracket 18 of the machine in the manner hereinabove described.

A serpentine slice-receiving and discharge spout I52 has a receiving end I03 registering with the opening 82 in the bracket 18 and has a downwardl curving wall I04 for deflecting the best slices downwardly through a discharge opening I05 at the opposite end of this spout. Spout I 02 is mounted in place by means of a bracket I86 mounted upon its lower side and secured by a fastening device I01 to the frame cross member I6. A second spout holding bracket I08 is secured to its upper side and is secured to the upper portion II of the frame ID by means of a fastening device I09.

Referring now to Figs. 1 and 2, there is shown at one side of the slice discharge spout I02 a knife guard casing I I I secured in place upon the frame member m by a wing-nut fastening device I I2. Guard casing III has a rectangular opening II3 therein which is traversed by guard bars H4. The opening I I3 permits inspection of the bank of knives 9! whereas the bars H4 preclude inadvertent projection of an operators fingers into the knife bank where they might be injured, if the machine were in operation, by being struck and forced into the knives by a catapulted beet.

A similar guard device III (not shown) is mounted at the opposite side of the spout I02 and of the knife bank frame 83.

Operation of the machine The machine is placed in operation by starting the electric motor M whereby power is transmitted from the pulley 6| on the armature shaft 2 of this motor through the belt 63 to the pulley S2 with which the impeller drive shaft 33, Figs. 2, l and 6, is constrained for rotation. Shaft 33 is caused to rotate clockwise as viewed in Fig. 4 thus causing the impeller 32 to revolve clockwise about the axis aa. Beets, graded as to size, are fed from the hopper 2| downwardly through the chute 22 onto the lower part of the trough formgamers:

ing shoulders: 23: and; 2 93 which; converge radially:

be seen imEig; 6E 'I'hexnotch i intthe beetpimpellen'shank-AEZfacilitateszentry'oil thEEbBEbSgilltD;

the space between 1711611033181! partsof a. chamber. CHiformedsbetweenzrelatively.widely spacedicentraltportions CR'of the: casing endiwallsdfi and 26: After. a;.beetiarriveszinzregistryrwith the im-- pelleirshanhllawhile.restingsupon the lower portion'. of: thetrough: forming shoulders 2 B and 29} Figs; A and-.6; thiszshank portion will engage and propel the beetialong the trough: 2:1. formedzbysuch shoulcuersa Asi the loeetlis thus advanced alongtheztrough 21b it isguided thereby in: a spiral: pat-1r progressively departing radially from the axis: a -et and to=thereby accelerate from a relatively. slow: curviliiiear speed at the time of contactwiththe'impcllen shank to-a relatively fast curvilinearspeed atthe time i it'- is engaged bythe radially outer end ofthe impeller 32 and catapulted thereby downwardly through the guidepasSage-GB. As the-beet is thus-propelled along the guide trough 2 it roll'supon' the' radially outwardly convergingshoulders 28 and 2E) thereof-which orient thebeetsothat the principal axis thereof passing through the opposite regions thereof respectively wherethetop and root have been removed approximates parallelism with theaxis-a -a: Thisorientation of the beet is facilitated by a"- cavity 6 extending lengthwise of thepropelling; facePF of the-impeller, said elongated cavityhaving atransverse curvature;

upon the periphery of the propeller face PF similar to the surface portion of the beets engaged thereby. Therefore" at" the time the' beets are catapulted from the radially outer end ofJtheimpeller: 32 into the: discharge passage ES'they will be, spinning abouttheir principal axes which are arranged generally in parallelism with the impelleraxis w-aandtransversely of the slicing; knives 97:: This orientation of the beets with respect to, the knives is maintained because, of gyroscopic force upon these rapidly rotating beets. Thus the beetswill be sliced by the knives 9'! transversely ofjtheir. principal axes pursuant to inertia carrying them into. andthrough thev knife bank. The beets arejcut into parallel slices of uniform thickness corresponding to the lateral spacing of the knives. By arranging the wives in the echelon formation illustrated the centermostknife ill'will first enter the beet and. immediately. thereafter, successive pairs of'knives spaced equally from opposite sides of the upper.- most knife 9? willsuccessively enter the beet, the knives of each pair entering the beet simultaneously thereby avoiding unequally applied forces which would tend to disturb orientation of'the beet. A further advantage of the echelon arrangement of knives is to avoid compression of the beet slices with attendant crushing of the vegetable cellular structure. Moreover this avoidance of gripping or compression cf'the beet between the knives diminishes resistance to the passage of the beet therebetween, as does the thin character of these-tensile knives. A corresponding slower speed is therefore possible for the rotating impeller.

It is desired to gradually diminish the speed of the beet slices emerging from the lower side of the bank of knives 91" through the opening 82. This is accomplished'by the sinusoidal spout I02 w-hichgraduallychanges the course-of'movement of the slices from a downwardly direction as theyemerge from the knife-banktoan upwardly direction as these slices slidingly traverse a lower-- 8; curved-'wall W'ofzthe-spout. The direction of the slices is again'.reversed asthey=traversean-upper curved wall W before being discharged downwardly through. the discharge opening: I05 into a-suitablereceptacle not shown. I his changing the sinusoidal: spout. I112: diminishesv their speedclearly and" concisely illustrating the same, we claim::

1; In. a beet-slicing machine, a beet-receiving and feeding trough having a beet-receiving terminus adjacent an axis and a beet discharge terminus relatively remote from said axis, said trough extending. spirally about such axis from the. receiving. terminus :and i progressively departingradially from such axis as such trough extends from saidterminus tothe discharge terminus,.said troughhaving a paddle-receiving slot bisecting the same from said receiving terminus throughout a substantialportion thereof extending-toward the discharge terminus, and a beetpropelling, paddle rotatable about said axis and extending radially therefrominto saidslot.

2.; The combination set forth in claim 1 wherein, there; is; a: bank. of. laterally spaced slicing knives registering with said trough adjacent the discharge terminus thereof, the cutting edges-cf said knives extending. transversely: of the trough at; said? dischargeterminusand lying within respectivezplanes disposed inparallelism with the axis of the trough at said discharge terminus.

3; The combinationset forthin claim 2whereinthe cutting. edges. of said knives are in an echelonformation with the centermost of said edges disposed nearer to saidterminusthan the edges on opposite sides of'said centermost edge.

4. The combination set forth in claim 2 wherein the planesicontaining the cutting edges of said knives are substantially perpendicular to said axisabout which the paddle is rotatable.

5.v The combination set forthin claim 2 wherein: there is' a: sinusoidalslice decelerating passage having a slice-receiving end upon the opposite side;of.ttheknife banksfrom the troughdischarge terminus, and saidisinusoidal passage being open at the'opposite endithereof for discharging the slices therefrom;

6. In a beet-slicing machine; a beetreceiving and:guiding-trough having-a beet receiving inner terminus and an outer discharge terminus and extending; spirally from. said receiving terminus substantially. withina plane to said discharge terminus, said trough also having a beet impeller receiving. slot bisecting its inner terminus within said: plane: and extending lengthwise thereof at least: substantiallyetothe' discharge terminus; an impeller: rotatable about; an axis adjacent the inner: terminusaof. the trough. and: extending perpendicularl'y; to. said; plane, said impeller being adapted tosweep throughsaid slot pursuant to rotation about said axis, abankof "Slicing knives having cutting edges in registry with the discharge terminusof the trough forintersecting articles discharged from the trough' through said discharge terminus, andthecutting edges of said knivesibeing: in laterally spaced parallelism within=-respeotive= planes parallel with that occupied by-the trough.

7i hr at beet-slicing machine; a casing comprising a pair of laterally spaced substantially parallel walls, one of said walls having a beetreceiving opening therein, said wall also having a spiral cavity within its inner periphery, the other wall having a spiral cavity within its inner periphery in opposed conformity with the firstnamed cavity and being effective complementally therewith to form a spiral trough within said walls, said trough having an inner terminus communicative with the beet-receiving opening and also having an outer terminus, said trough extending spirally outwardly from its inner terminus to its outer terminus while also extending about an axis which intersects said opening perpendicularly to the walls; an impeller hub journalled in said casing coaxially with said axis, an impeller constrained for rotation with said hub and extending radially therefrom between said walls for sweeping therebetween through the trough during rotation of the hub, said impeller being adapted to engage and propel a beet along said trough from the inner terminus thereof and for discharging the same through the outer terminus, and a bank of slicing knives disposed adjacent the outer terminus of the trough for intercepting beets discharged from said outer terminus and cutting the same into slices as they pass through the knife bank;

8. The combination set forth in claim 7 wherein each of said spiral cavities comprises a shoulder extending lengthwise thereof and along which a beet propelled by said paddle can roll while maintaining contact with each thereof by virtue of centrifugal force acting upon said beet, said shoulders converging toward one another while extending transversely of the trough and radially outwardly of said axis.

9. In a beet-slicing machine, a beet-receiving and guiding trough having a beet-receiving inner terminus and a discharge outer terminus, said trough extending spirally outwardly substantially within a plane from the receiving terminus to the discharge terminus, said trough also having an impeller-receiving slot bisecting its receiving terminus within said plane and extending lengthwise of said trough at least substantially to the discharge terminus thereof, an impeller rotatable about an axis adjacent the receiving terminus of the trough and extending perpendicularly to said plane, said trough comprising shoulders extending lengthwise thereof upon respective opposite sides of said slot, said shoulders converging toward said slot as they extend transversely of the trough and radially from said axis, said impeller being adapted to sweep through said slot pursuant to rotation about said axis, a bank of slicing knives having cutting edges in registry with the outer terminus of the trough for intersecting articles discharged from the trough through said discharge terminus, the cutting edges of said knives being in laterally spaced parallelism and being within planes parallel with that occupied by the trough.

10. In a slicing knife unit, the combination of a pair of laterally spaced knife supporting brackets each including a double series of shoulders and risers arranged in V-formation, knife supporting studs projecting outwardly from said risers, a series of linear knives each having means at one end thereof for attaching to the studs in the risers of one of said brackets and each having a series of means at the opposite ends thereof for attaching to the studs in the risers of the other bracket, each knife also having a cutting edge of which all are disposed toward the upper edges of the risers with which they are respectively associated to provide an echelon arrangement of knife cutting edges, and thrust means spaced transversely from the knives to provide clearance for cuttable objects to approach the knife edges, and said thrust means exerting thrust force urging th brackets apart endwise of the knives for placing the knives under tension.

11. In a slicing knife unit, the combination of a pair of laterally spaced knife supporting brackets each including a double series of sho ders and riser in V-fcrmation, said risers being in parallel planes and each having an upper edge adjacent one of said shoulders immediately thereabove, a series of linear knives .each having means at one end thereof for attaching to a respective one of the studs in the risers of one of said brackets and each having means at the opposite end thereof for attachin to a respective stud in the risers of the other bracket, each knife also having a cutting edge of which all are disposed toward the upper edges of the risers with which they are respectively associated and said knives also being disposed fiatwise against their respectively associated risers to provide an echelon arrangement of knives in parallel planes, and thrust means spaced transversely from the knives to provide clearance for cuttable objects to approach the knife edges while moving perpendicularly to such edges in parallelism with said planes, said thrust means extending in parallelism with the knives in force-transmitting relation with said brackets and exerting thrust force between the brackets for urging them apart endwise of the knives for placing the knives under tension.

12. The combination set forth in claim 11 wherein there are end plates respectively for said brackets, said end plates having opposed inner faces disposed in parallel planes, wherein said brackets each have an outer face assembled respectively flatwise against the inner faces of the end plates, means for attaching the brackets to the end plates in said assembly therewith, and wherein said thrust means is comprised of endwise expansible elements extending between and secured to said plates.

13. The combination set forth in claim 12 wherein each of said brackets comprises components each havin a series of the risers and shoulders thereon and an inner edge extending in parallelism with the risers, each bracket component containing a series of stud-receiving bores communicating between the inner edge thereof and respective of the risers, said bores having countersunk large diameter portions adjacent their associated inner edge of their bracket component, headed knife supporting studs having their heads within said counterbores and shanks projecting endwise outwardly of the bores through the risers for attachment of the knives thereto, and means for securing the components of each bracket in complemental assembly with their inner edges in contiguity while the studs are assembled therewith as aforesaid.

References Cited in the file of this patent UNITED STATES PATENTS 

